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HIVES (URTICARIA)
HIVES (URTICARIA) – TYPES, CAUSES, FEATURES AND TREATMENT Hives (urticaria) is a common, recurrent, hypersensitivity reaction of the skin characterized by formation of transient wheals which are extremely itchy, coming suddenly and causing lot of distress. Both sexes and all ages are effected. Its incidence ranges from 15-25% of the population. Hives (urticaria) may be acute or chronic, localized or generalized. It may be idiopathic, IgE mediated, complement mediated or due to physical causes such as heat and cold, sunlight and physical agents etc. Acute urticaria results from ingestion of certain foods, drugs inhalants and after Bee Stings. It is characterized by formation of large, wheals and is IgE dependent in persons with atopic background. It comes suddenly and is of short duration. Attack is associated with pruritis and skin appears normal after wards. Chronic Hives (urticaria) This is defined as disease lasting for more than 6 weeks. It is considered idiopathic in majority of patients (80-90%) and is not IgE dependant. It affects predominantly adults and is twice as common in women as men. Emotional factors play important role in exacerbating the condition. Many factors including salicylates dyes in food substances and preservatives, intestinal parasites, septic foci in the body are important in precipitating the disease. For its development the retention increase in weight occurs. state of tissues is more important since it is an allergic reaction to a foreign Protein. Urticaria - hives Clinical types of Hives (urticaria) 1. Physical urticaria: It is type of urticaria which is produced by physical conditions like pressure, scratching etc. Mostly it is asymptomatic but symptoms occur after local trauma to the skin. Mild scratching may produce erythema and wheals (DERMOGRAPHISM). 2. Cold Urticaria : It occurs in children and young adults. Exposure to cold in the form of cold climate, freezing temperature contact with cold objects from the freezer trigger the reaction. Application of ‘ice cube’ to the skin of such people elicits a wheal and establishes the diagnosis. 3. Solar urticaria: Exposure to sun, ultraviolet light etc produces urticaria especially during summer months in a very short time, may be minutes. There is itchy pale or red swelling at the site. 4. Cholinergic urticaria: It is common in young adults and is mediated by acetyl choline. Lesions are small (1-3 mm) red, papular wheals surrounded by erythema and last for 30-60 minutes. Attacks are triggered by hot baths, exercise and after emotional stress. 5. Aquagenic urticaria: It is an uncommon form. Contact with water produces itching with or without wheals. Clinical picture of Hives (urticaria) Sudden appearance of papules or plaques with well demarcated borders and surrounded by erythematous halo, varying in size from pea size to several cms, and marked itching characterize clinical picture of urticaria. Lesions are transient and appear within minutes and last usually for a short period. Wheals which are circumscribed and transient erythematous oedematous lesions constitute essential lesion. Depending on the duration of lesion, skin appears normal after wards. While there is no specific predilection for any part of body but trunk and thighs are commonly involved. Pathology There is edema of the dermis or subcutaneous tissue and passage of fluid out of the vessel may accompany dilatation caused by mediators such as histamine derived from mast cells and other compounds such as eicosanoids and neuropeptides. Lesions in acute IgE mediated urticaria (hives) result from antigen induced release of biologically active material. This increases venular permeability and modulates the release from other cells of vaso active compounds. Investigations There is usually eosinophilia. Stools should be looked for any parasite. There may be hypocomplementemia. Course of the disease Where there is offending agent localized, the disease may be controlled. In more than 50% of patients, the person is free from urticaria in period ranging from 1-2 years while in others it may have a very chronic course. Management It may be very prolonged affair. A thorough search should be made for any drug, food item, septic foci, intestinal parasites, which might be responsible for causing Hives (urticaria). When a patient of urticaria (hives) presents, he/she has usually distressing symptoms of itching. Local application of calamine lotion or cold compresses shall offer relief. Systemic therapy includes administration of antihistamines like first generation H-I antagonists (chlorpheneramine maleate, diphenhydramine, hydroxyzine) are effective but their only drawback is that they are sedating. Non-Sedating antihistamines (cetirizine, loratadine and fexofenadine) are equally effective and preferred. Combination of an H receptor antagonist with an H2-blocker such as RANITIDINE may stop attacks when other treatments fail. Mast cell stabilizer (Ketotifen) which is an antihistamine inhibits stimulation and mediator release by immunogenic and inflammatory cells like mast cells and leukocytes, is an equally effective alternatives drug in resistant cases of urticaria (hives). Systemic corticosteroids are not preferred in treatment of urticaria, except for short periods. In severe forms of acute urticaria Adrenaline (1: 1000) is also given subcutaneously (0.5-1 ml) in very severe cases of urticaria. Causes of Hives (urticaria) 1. Idiopathic 2. Immunologic mechanisms (a) IgE Mediated (b) Complement mediated 3. Non allergic causes (a) Drugs (Penicillin, Aspirin) (b) Foods (Mild & milk products, eggs, fish) © Food additives. (d) Inhalants (Pollens, House dust) (e) Parasitic infestations. (f) Physical (Cold, sun exposure, Pressure, scratching) (g) Insect bites Category:GC Writers Resources